ruler

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A ruler seems like a pretty simple device; just a nice straight piece of material with some marks on it. There are some improvements out there to the basic design, like making it out of something flexible or printing a few useful crib notes and formulas on it so you have a handy reference. But for the most part, we can all agree that ruler technology has pretty much plateaued.

Even if you’ve never commanded one of the blinkenlight behemoths that inspired the Digirule2, this is an excellent way to get some hands-on experience with early computer technology. Available for about the cost of a large pizza on Tindie, it represents one of the easiest and most cost-effective ways to tell your friends that as a matter of fact you have programmed a computer in binary.

The Digirule2 is powered by a Microchip PIC18F43K20, and is programmed by punching binary in one byte at a time with a bank of eight tactile switches. To make things a little easier, programs can be saved to the internal EEPROM and loaded back up just as easily thanks to the handy buttons next to the power switch. Now all you’ve got to do is figure out what all those blinking LEDs mean, and you’ll be in business.

Friday was the 2016 Open Hardware Summit, a yearly gathering of people who believe in the power of open design. The use of the term “summit” rather than “conference” is telling. This gathering brings together a critical mass of people running hardware companies that adhere to the ideal of “open”, but this isn’t at the exclusion of anyone — all are welcome to attend. Hackaday has built the world’s largest repository of Open Hardware projects. We didn’t just want to be there — We sponsored, sent a team of people, and thoroughly enjoyed ourselves in the process.

Join me after the break for a look at the talks, a walk through the swag bags, and a feel for what this wonderful day held.

Like [Brad], we’ve seen a number of PCB rulers out there. [Brad] was looking to take the idea and run with it. His DigiRule is a ruler with a logic gate simulator. What he built is a mash-up between PCB rulers, and the concept of electronic business cards.

All told it simulates seven logic gates, four flip-flops, and includes a four-bit counter. On one end of the ruler a CR1220 battery feeds the 18F43K20 which is performing the logic operations using buttons and LEDs. Of course the truth tables are printed on the back silk-screen, but playing with the lights is a lot more fun. We do find it fairly amusing that the centimeters on the bottom of the ruler are notated in binary.

Hobby CNC mills have made rapid prototyping easier and faster for hackers. One really useful application is quickly fabricating your own milled PCB’s. [proto logical] built a Reference PCB Business Card using his CNC mill after repeatedly coming across other hackers who were not too convinced about the capabilities of CNC mills in routing PCB’s (also referred to as isolation milling). He thought of making a business card sized reference PCB to show around when he bumps into such folks.

To keep it useful, he included inch and centimetre scales, 0.1″ grid of holes, reference track widths from 16 mil to 66 mil, a few common drill holes and vias and some SMD foot prints. The single sided board is 50 mil thick, so it doesn’t bulk up his wallet. He’s posted the Eagle board file (direct download) and G-code (text file) for those interested in milling their own reference boards. The idea isn’t new – it’s been tried several times in different form factors in the past, generally using more traditional techniques. [proto logical] got inspiration from [Rohit Gupta’s] TinkerRule – The Maker’s Swiss Army Knife. Then there’s the very popular uRuler made by [Dave Jones] of EEVBlog fame. If you have any suggestions on improving the design, chime in with comments here.

Thanks to [ACG] for sending in this tip that he dug up while looking for CNC routed PCB’s.

Just about every engineer needs to take a drawing class, but until now we surprisingly haven’t seen electronics thrown into rulers, t-squares, and lead holders. [Anirudh] decided to change that with Glassified. It’s a transparent display embedded in a ruler that is able to capture hand drawn lines. These physical lines can be interacted with or measured, turning a ruler into a bridge between a paper drawing and a digital environment.

For the display, [Anirudh] mounted a transparent TOLED display with a digitizer input into a ruler. The digitizer captures the pen strokes underneath the ruler, and is able to interact with the physical lines, either to calculate the length and angle of lines, or just to bounce a digital ball inside a hand-drawn polygon.

There’s no word on how this display is being driven, or what kind of code is running on it. [Anirudh] said he will have some schematics and code available up on his website soon (it’s a 404 right now).

[Koogar] came up with a useful tool for checking the measurements of your layouts in Eagle CAD. He calls it the Gridrunner; a custom part that adds a 200mm ruler to your design. Tick marks are in 1/10th of a millimeter increments for great accuracy when used with the zoom feature of Eagle. Once you’ve got the layout just right, delete the ruler from your design and export it for fabrication. [Koogar] does mention that the beta version of Eagle 6 has a new measuring tool, but he still thinks the Gridrunner offers some things that the built-in tool doesn’t. See just how handy it is in the video after the break. The measuring starts about 1:40 into it.

We found it interesting that [Koogar] is using Eagle for quite a bit more than PCB design. We’ve used it for laying out a drilling template for face plates before, but he’s going far beyond that. He uses the library editor to recreate the parts of his CNC machine which he says are then really easy to align. From there, he exports the CAM files for mounting brackets. Do you use Eagle for something other than PCB design? Let us know about it by leaving a comment. Continue reading “Gridrunner: A Custom Part For Measuring In Eagle CAD”→